scholarly journals Physiological responses of Daphnia pulex to acid stress

2009 ◽  
Vol 9 (1) ◽  
pp. 9 ◽  
Author(s):  
Anna K Weber ◽  
Ralph Pirow
Keyword(s):  
Physiological Responses ◽  
Daphnia Pulex ◽  
Acid Stress

Inter- and Intra-specific Variability in the Response of Zooplankton to Acid Stress

1985 ◽  
Vol 42 (11) ◽  
pp. 1749-1754 ◽  
Author(s):  
Edmund E. Price ◽  
Michael C. Swift
Keyword(s):  
Natural Populations ◽  
Daphnia Pulex ◽  
Acid Stress ◽  
Intraspecific Variability ◽  
Early Summer ◽  
Low Ph ◽  
Acid Sensitivity ◽  
Chaoborus Americanus ◽  
Acute Bioassays ◽  
Mesocyclops Edax

We measured the toxicity of sulfuric acid to natural populations of Daphnia pulex, D. galeata mendotae, Simocephalus serrulatus, Mesocyclops edax, Chaoborus americanus, and C. punctipennis. Organisms were collected in the spring and fall from acidic (pH 5.4) and circumneutral (pH 6.3–7.5) ponds, and their response to low pH was compared in 48- or 96-h acute bioassays. Based on 48- and 96-h LC50, cladocerans were most susceptible to acid stress, followed by Mesocyclops and Chaoborus larvae. Simocephalus was the most tolerant cladoceran, followed by D. pulex then D. galeata mendotae. Daphnia populations tested in the spring or early summer were more tolerant of low pH than those tested in the fall. Mesocyclops edax from an acid pond were more tolerant than those from a neutral pond. The response of the two Chaoborus species to low pH were quite similar; their 96-h LC50 (2.00, 2.09) was two pH units lower than those of cladocerans and one pH unit lower than that of M. edax. Our data demonstrate interspecific variability in acid sensitivity and suggest intraspecific variability due to habitat and season.

The effect of acid stress on survivorship and reproduction of Daphnia pulex (Crustacea: Cladocera)

1982 ◽  
Vol 60 (4) ◽  
pp. 573-579 ◽  
Author(s):  
W. E. Walton ◽  
S. M. Compton ◽  
J. D. Allan ◽  
R. E. Daniels
Keyword(s):  
Population Growth Rate ◽  
Daphnia Pulex ◽  
Acid Stress ◽  
Pond Water ◽  
Low Ph ◽  
Laboratory Simulation ◽  
Zooplankton Species ◽  
Field Surveys ◽  
Delayed Onset ◽  
Acute Test

Laboratory simulation of acid stress to a common cladoceran, Daphnia pulex, was conducted in pond water of varying acidity due to addition of H2SO4. An acute test using exposure times of 1 to 96 h and pH levels of 3.7 and 6.5 revealed virtually no effect at 4.3 and higher, while 4.2 and lower severely reduced survivorship. Very short (3-h) exposures caused nearly complete mortality at pH 3.7, while > 12 h exposure caused high mortality at pH of 4.0–4.2. A chronic 21-d life table test indicated a gradually increasing impairment of population growth rate potential (r) at pH 5.0 and below. This was due primarily to reduced survivorship and delayed onset of reproductive maturity. Those individuals which survived at lower pH levels produced broods equivalent to unstressed daphnids. While the tolerance of D. pulex to low pH does not appear to have been reported from field surveys, our results are in close agreement with the observed effects of increasing acidity on the distribution of other zooplankton species.

Physiological Responses to Acid Stress in Crayfish (Orconectes): Haemolymph Ions, Acid–Base Status, and Exchanges with the Environment

1986 ◽  
Vol 43 (5) ◽  
pp. 1017-1026 ◽  
Author(s):  
Chris M. Wood ◽  
Mary S. Rogano
Keyword(s):  
Physiological Responses ◽  
Acid Stress ◽  
Environmental Water ◽  
Severe Metabolic Acidosis ◽  
Acid Base ◽  
Orconectes Propinquus ◽  
Unidirectional Flux ◽  
Moderate Depression ◽  
Extracellular Compartment ◽  
Acid Base Status

Exposure of Orconectes propinquus for 5 d to pH = 4.0 (H2SO4) in decarbonated soft water ([Ca2+] = 0.20 mequiv∙L?1) caused a severe metabolic acidosis and a moderate depression of [Na+] and [Cl−] in the haemolymph. Lactate did not accumulate. Acidosis was caused by a large uptake of acidic equivalents from the environmental water, of which more than 95% was stored outside the extracellular compartment after 5 d. Carapace buffering was probably involved, because haemolymph [Ca2+] rose substantially and Ca2+ was lost to the environment. Similar net effluxes of K+ indicated that acidic equivalents also penetrated the intracellular compartment. [Formula: see text] was also lost during acid exposure. Haemolymph [Na+] fell more than [Cl?] because of greater net losses to the water. Unidirectional flux analyses with radiotracers demonstrated that negative net Na+ and Cl− balance resulted from partial inhibition of influx components; effluxes were little affected. All flux effects were reversed during 5 d of recovery at pH = 7.5. Haemolymph ionic responses in Orconectes rusticus differed in showing a smaller, equimolar reduction of [Na+] and [Cl−] and a much larger elevation of [Ca2+]. At a mechanistic level, the responses of crayfish to acid stress appear very different from those of teleost fish.

Physiological responses ofMicrocystis aeruginosaPCC7806 to nonanoic acid stress

2009 ◽  
Vol 24 (6) ◽  
pp. 610-617 ◽  
Author(s):  
Ji-Hai Shao ◽  
Xing-Qiang Wu ◽  
Ren-Hui Li
Keyword(s):  
Physiological Responses ◽  
Acid Stress ◽  
Nonanoic Acid

Misophonia: An Evidence-Based Case Report

2020 ◽  
Vol 29 (4) ◽  
pp. 685-690
Author(s):  
C. S. Vanaja ◽  
Miriam Soni Abigail
Keyword(s):  
Quality Of Life ◽  
Case Report ◽  
Case History ◽  
Pure Tone ◽  
Physiological Responses ◽  
Evidence Based ◽  
Management Option ◽  
Pure Tone Audiogram

Purpose Misophonia is a sound tolerance disorder condition in certain sounds that trigger intense emotional or physiological responses. While some persons may experience misophonia, a few patients suffer from misophonia. However, there is a dearth of literature on audiological assessment and management of persons with misophonia. The purpose of this report is to discuss the assessment of misophonia and highlight the management option that helped a patient with misophonia. Method A case study of a 26-year-old woman with the complaint of decreased tolerance to specific sounds affecting quality of life is reported. Audiological assessment differentiated misophonia from hyperacusis. Management included retraining counseling as well as desensitization and habituation therapy based on the principles described by P. J. Jastreboff and Jastreboff (2014). A misophonia questionnaire was administered at regular intervals to monitor the effectiveness of therapy. Results A detailed case history and audiological evaluations including pure-tone audiogram and Johnson Hyperacusis Index revealed the presence of misophonia. The patient benefitted from intervention, and the scores of the misophonia questionnaire indicated a decrease in the severity of the problem. Conclusions It is important to differentially diagnose misophonia and hyperacusis in persons with sound tolerance disorders. Retraining counseling as well as desensitization and habituation therapy can help patients who suffer from misophonia.

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